U.S. patent application number 17/047869 was filed with the patent office on 2021-05-27 for electrolyzed water generator and electrolyzed water generation system.
The applicant listed for this patent is PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.. Invention is credited to Kenichiro INAGAKI, Mami KURODA, Tetsuya MAEKAWA, Shunsuke MORI, Minoru NAGATA.
Application Number | 20210155509 17/047869 |
Document ID | / |
Family ID | 1000005400529 |
Filed Date | 2021-05-27 |
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United States Patent
Application |
20210155509 |
Kind Code |
A1 |
INAGAKI; Kenichiro ; et
al. |
May 27, 2021 |
ELECTROLYZED WATER GENERATOR AND ELECTROLYZED WATER GENERATION
SYSTEM
Abstract
An electrolyzed water generator includes anode, cathode, and
cation exchange membrane provided between anode and cathode so as
to be in contact with at least one of anode and cathode. Gaps in
which a flow of water occurs are present between cation exchange
membrane and at least one of anode and cathode.
Inventors: |
INAGAKI; Kenichiro; (Shiga,
JP) ; MORI; Shunsuke; (Osaka, JP) ; NAGATA;
Minoru; (Shiga, JP) ; KURODA; Mami; (Kyoto,
JP) ; MAEKAWA; Tetsuya; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD. |
Osaka |
|
JP |
|
|
Family ID: |
1000005400529 |
Appl. No.: |
17/047869 |
Filed: |
May 15, 2019 |
PCT Filed: |
May 15, 2019 |
PCT NO: |
PCT/JP2019/019203 |
371 Date: |
October 15, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F 1/46109 20130101;
C02F 2001/46133 20130101 |
International
Class: |
C02F 1/461 20060101
C02F001/461 |
Foreign Application Data
Date |
Code |
Application Number |
May 25, 2018 |
JP |
2018-100662 |
May 25, 2018 |
JP |
2018-100672 |
May 25, 2018 |
JP |
2018-100683 |
Claims
1. An electrolyzed water generator comprising: an anode; a cathode;
and a cation exchange membrane provided between the anode and the
cathode and being in contact with at least one of the anode and the
cathode, wherein a gap in which a flow of water occurs is present
between the cation exchange membrane and the at least one of the
anode and the cathode.
2. The electrolyzed water generator according to claim 1, wherein
the gap is a groove or a cutout provided in at least one of a first
surface and a second surface, the first surface being a surface of
the cation exchange membrane and facing the at least one of the
anode and the cathode, the second surface being a surface of the at
least one of the anode and the cathode and facing the cation
exchange membrane.
3. The electrolyzed water generator according to claim 1, wherein
the cation exchange membrane is provided in contact with the anode
and the cathode, the cation exchange membrane includes a membrane
hole penetrating the cation exchange membrane to expose a third
surface, the third surface being a surface of the anode and facing
the cation exchange membrane, the cathode includes a cathode hole
penetrating the cathode to communicate with the membrane hole, and
the cathode hole of the cathode includes a high electrical
resistance material having an electrical resistance value higher
than an electrical resistance value of the cathode.
4. The electrolyzed water generator according to claim 1, wherein
the gap is a path through which water flows from one end of the
cation exchange membrane to another end of the cation exchange
membrane.
5. The electrolyzed water generator according to claim 3, wherein
the high electrical resistance material is a coating material
applied to the cathode hole.
6. An electrolyzed water generator comprising: an anode; a cation
exchange membrane provided in contact with the anode, the cation
exchange membrane including a membrane hole penetrating the cation
exchange membrane to expose a first surface, the first surface
being a surface of the anode and facing the cation exchange
membrane; a cathode provided in contact with the cation exchange
membrane and having a frame shape; and a high electrical resistance
material provided on an inner periphery of the frame shape and
being in contact with an inner peripheral surface of the frame
shape and having an electrical resistance value higher than an
electrical resistance value of the cathode, the high electrical
resistance material including a communication hole penetrating the
high electrical resistance material to communicate with the
membrane hole.
7. The electrolyzed water generator according to claim 3, wherein
the cathode contains a stainless steel material, and the high
electrical resistance material contains a fluorine resin
material.
8. An electrolyzed water generation system comprising: the
electrolyzed water generator according to claim 1; and a controller
that controls the electrolyzed water generator, wherein the
controller intermittently applies a voltage between the anode and
the cathode.
9. The electrolyzed water generation system according to claim 8,
further comprising: a flow path that supplies the water to the
electrolyzed water generator; a pump that supplies the water to the
flow path; and a flow path change mechanism that is switched to
intermittently supply the water from the flow path to the
electrolyzed water generator, wherein during a period where the
voltage is not applied, the controller causes the pump and the flow
path change mechanism to supply the water from the flow path to the
electrolyzed water generator.
10. An electrolyzed water generation system comprising: a trunk
flow path supplied with water; a first branch flow path branched
from the trunk flow path; an electrolyzed water generator that
includes an anode, a cathode, and a cation exchange membrane
provided between the anode and the cathode, the electrolyzed water
generator being connected to the first branch flow path, and
switched between a generation state where electrolyzed water is
generated from the water flowing through the first branch flow path
and a non-generation state where the electrolyzed water is not
generated; a second branch flow path that is branched from the
trunk flow path and supplies the water, flowing through the trunk
flow path, to a downstream of the trunk flow path; and a flow path
change mechanism that is switched between a first state where the
water is supplied from the trunk flow path to the first branch flow
path and a second state where the water is supplied from the trunk
flow path to the second branch flow path.
11. The electrolyzed water generation system according to claim 10,
further comprising a controller that controls the electrolyzed
water generator, wherein the controller intermittently applies a
voltage between the anode and the cathode to perform control to
switch the electrolyzed water generator from the non-generation
state to the generation state.
12. The electrolyzed water generation system according to claim 10,
wherein the anode is a first anode, the cathode is a first cathode,
the cation exchange membrane is a first cation exchange membrane,
the generation state is a first generation state, the
non-generation state is a first non-generation state, the
electrolyzed water generator is a first electrolyzed water
generator, and the electrolyzed water generation system further
comprises a second electrolyzed water generator including a second
anode, a second cathode, and a second cation exchange membrane
provided between the second anode and the second cathode, the
second electrolyzed water generator being connected to the second
branch flow path, and switched between a second generation state
where second electrolyzed water is generated from the water flowing
through the second branch flow path and a second non-generation
state where the second electrolyzed water is not generated.
13. The electrolyzed water generation system according to claim 12,
further comprising: the first electrolyzed water generator; the
second electrolyzed water generator; and a controller that controls
the flow path change mechanism, wherein when the controller
performs control to switch the flow path change mechanism from the
second state to the first state, the controller performs control to
switch the first electrolyzed water generator from the first
non-generation state to the first generation state during a period
where the second electrolyzed water generator is controlled to be
switched from the second generation state to the second
non-generation state and the flow path change mechanism is
controlled to be switched from the second state to the first state,
and when the controller performs control to switch the flow path
change mechanism from the first state to the second state, the
controller performs control to switch the second electrolyzed water
generator from the second non-generation state to the second
generation state during a period where the first electrolyzed water
generator is controlled to be switched from the first generation
state to the first non-generation state and the flow path change
mechanism is controlled to be switched from the first state to the
second state.
14. The electrolyzed water generation system according to claim 10,
further comprising a purification device that is connected to the
second branch flow path, generates purified water from the water
flowing through the second branch flow path, and supplies the
generated purified water to a downstream of the second branch flow
path.
15. The electrolyzed water generation system according to claim 10,
further comprising a purification device that is connected to the
trunk flow path, generates purified water from the water flowing
through the trunk flow path, and supplies the generated purified
water to the downstream of the trunk flow path, wherein the
electrolyzed water generator uses the purified water as the water
and generates the electrolyzed water from the purified water.
16. The electrolyzed water generation system according to claim 10,
wherein the flow path change mechanism has a first valve connected
to the first branch flow path and a second valve connected to the
second branch flow path, in the first state, the first valve is
opened, and the second valve is closed, and in the second state,
the first valve is closed, and the second valve is opened.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an electrolyzed water
generator and an electrolyzed water generation system.
BACKGROUND ART
[0002] Conventionally, an electrolyzed water generation system has
been developed. A conventional electrolyzed water generation system
includes a flow path through which water flows and an electrolyzed
water generator connected to the flow path. The electrolyzed water
generator includes an anode, a cathode, and a cation exchange
membrane provided between the anode and the cathode. The
electrolyzed water generator is controlled by a controller to be
switched to either a generation state where electrolyzed water is
generated from water flowing through the flow path or a
non-generation state where electrolyzed water is not generated.
CITATION LIST
Patent Literature
[0003] PTL 1: Unexamined Japanese Patent Publication No.
2011-136333
SUMMARY OF THE INVENTION
[0004] In some of the above-described conventional electrolyzed
water generators, the anode and the cation exchange membrane are
provided in contact with each other, and the cation exchange
membrane and the cathode are provided in contact with each other.
In such a conventional electrolyzed water generator, the cation
exchange membrane is a non-woven fabric. Thus, a gap (whose details
are too small to show) closed to the extent that water does not
flow may be present at least one of between the anode and the
cation exchange membrane and between the cation exchange membrane
and the cathode.
[0005] In this case, gas generated near the anode, for example,
oxygen or ozone may be retained in the gap provided between the
anode and the cation exchange membrane and closed to the extent
that water does not flow. On the other hand, gas generated near the
cathode, for example, hydrogen may be retained in the gap provided
between the cation exchange membrane and the cathode and closed to
the extent that water does not flow. In these cases, the gas
retained between the anode and the cation exchange membrane and
between the cation exchange membrane and the cathode functions as
an insulator between the anode and the cathode. Thus, when a
voltage applied between the anode and the cathode is maintained at
a constant value, the concentration of electrolyzed water gradually
decreases. Therefore, in order to continue to use electrolyzed
water of a desired concentration, it is necessary to progressively
increase the voltage applied between the anode and the cathode
lager than a predetermined reference voltage.
[0006] The present disclosure has been made focusing on the
above-mentioned conventional problems. An object of the present
disclosure is to provide an electrolyzed water generator and an
electrolyzed water generation system that reduce a degree to which
a voltage applied between an anode and a cathode is made higher
than a reference voltage in order to continue to use a desired
concentration of electrolyzed water.
[0007] The electrolyzed water generator of the present disclosure
includes an anode, a cathode, and a cation exchange membrane
provided between the anode and the cathode so as to be in contact
with at least one of the anode and the cathode. A gap in which a
flow of water occurs is present between the cation exchange
membrane and at least one of the anode and the cathode.
[0008] In the electrolyzed water generator of the present
disclosure, the cation exchange membrane is provided in contact
with the anode and the cathode. The cation exchange membrane is
provided with a membrane hole penetrating the cation exchange
membrane such that a surface of the anode facing the cation
exchange membrane is exposed. The cathode is provided with a
cathode hole penetrating the cathode so as to communicate with the
membrane hole. The cathode hole of the cathode is provided with a
high electrical resistance material having an electrical resistance
value higher than an electrical resistance value of the
cathode.
[0009] The electrolyzed water generator of the present disclosure
includes an anode, a cation exchange membrane provided in contact
with the anode, a cathode provided in contact with the cation
exchange membrane and having a frame shape, and a high electrical
resistance material provided on an inner periphery of the frame
shape so as to be in contact with an inner peripheral surface of
the frame shape and having an electrical resistance value higher
than an electrical resistance value of the cathode. The cation
exchange membrane is provided with a membrane hole penetrating the
cation exchange membrane such that a surface of the anode facing
the cation exchange membrane is exposed. The high electrical
resistance material is provided with a communication hole
penetrating the high electrical resistance material such that the
high electrical resistance material communicates with the membrane
hole.
[0010] The electrolyzed water generation system of the present
disclosure includes an electrolyzed water generator and a
controller that controls the electrolyzed water generator. The
controller intermittently applies a voltage between the anode and
the cathode.
[0011] The electrolyzed water generation system of the present
disclosure includes a trunk flow path supplied with water, a first
branch flow path branched from the trunk flow path, an electrolyzed
water generator that includes an anode, a cathode, and a cation
exchange membrane provided between the anode and the cathode, the
electrolyzed water generator being connected to the first branch
flow path, and switched between a generation state where
electrolyzed water is generated from water flowing through the
first branch flow path and a non-generation state where the
electrolyzed water is not generated, a second branch flow path that
is branched from the trunk flow path and supplies the water,
flowing through the trunk flow path, to a downstream of the trunk
flow path, and a flow path change mechanism that is switched
between a first state where the water is supplied from the trunk
flow path to the first branch flow path and a second state where
the water is supplied from the trunk flow path to the second branch
flow path.
[0012] According to the electrolyzed water generator and the
electrolyzed water generation system of the present disclosure, it
is possible to reduce a degree to which a voltage applied between
the anode and the cathode is made higher than a reference voltage
in order to continue to use a desired concentration of electrolyzed
water.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is an external perspective view of an electrolyzed
water generation system of a first exemplary embodiment.
[0014] FIG. 2 is a longitudinal sectional view of an electrolyzed
water generator of the first exemplary embodiment.
[0015] FIG. 3 is an exploded perspective view of a layered
structure of the electrolyzed water generator of the first
exemplary embodiment.
[0016] FIG. 4 is an enlarged longitudinal sectional view of the
layered structure of the electrolyzed water generator of the first
exemplary embodiment.
[0017] FIG. 5 is a first diagram for explaining a chemical action
of the electrolyzed water generator of the first exemplary
embodiment.
[0018] FIG. 6 is a second diagram for explaining the chemical
action of the electrolyzed water generator of the first exemplary
embodiment.
[0019] FIG. 7 is a third diagram for explaining the chemical action
of the electrolyzed water generator of the first exemplary
embodiment.
[0020] FIG. 8 is a perspective view of a cathode of another example
of the electrolyzed water generator of the first exemplary
embodiment.
[0021] FIG. 9 is a timing chart for explaining a control mode of
the electrolyzed water generation system of the first exemplary
embodiment.
[0022] FIG. 10 is a schematic view of an electrolyzed water
generation system of a second exemplary embodiment.
[0023] FIG. 11 is a schematic view of the electrolyzed water
generation system of another example of the second exemplary
embodiment.
[0024] FIG. 12 is a graph showing a relationship between a voltage
applied between an anode and a cathode and a time during which the
voltage is applied in each of an intermittent drive operation and a
continuous drive operation of the electrolyzed water generation
system of the second exemplary embodiment.
[0025] FIG. 13 is a graph showing a relationship between a
concentration of ozone generated and the time during which the
voltage is applied between the anode and the cathode in each of the
intermittent drive operation and the continuous drive operation of
the electrolyzed water generation system of the second exemplary
embodiment.
[0026] FIG. 14 is a chemical formula of a cation exchange membrane
of an electrolyzed water generator of the electrolyzed water
generation system of the second exemplary embodiment.
[0027] FIG. 15 is a first diagram for explaining a chemical action
that occurs inside the electrolyzed water generator of the second
exemplary embodiment.
[0028] FIG. 16 is a second diagram for explaining the chemical
action that occurs inside the electrolyzed water generator of the
second exemplary embodiment.
[0029] FIG. 17 is a third diagram for explaining the chemical
action that occurs inside the electrolyzed water generator of the
second exemplary embodiment.
DESCRIPTION OF EMBODIMENTS
[0030] Hereinafter, an electrolyzed water generation system and an
electrolyzed water generator used therein of each exemplary
embodiment will be described with reference to the drawings. In the
following exemplary embodiments, portions having the same reference
numerals have the same function as each other even if there is a
slight difference in shape in the drawings, unless otherwise
specified.
First Exemplary Embodiment
[0031] Electrolyzed water generation system 1000 of a first
exemplary embodiment will be described with reference to FIGS. 1 to
9.
(Structure of System)
[0032] As shown in FIG. 1, electrolyzed water generation system
1000 includes a flow path through which water flows. The flow path
provided in electrolyzed water generation system 1000 includes
trunk flow path 15, upstream-side first branch flow path 10A,
downstream-side first branch flow path 20A, upstream-side second
branch flow path 10B, and downstream-side second branch flow path
20B. Trunk flow path 15 receives water delivered by pump P. That
is, the water is supplied from pump P to trunk flow path 15.
Upstream-side first branch flow path 10A and upstream-side second
branch flow path 10B are branched from trunk flow path 15,
respectively. In the present exemplary embodiment, the water
supplied from pump P is also referred to as raw water.
[0033] First branch flow paths 10A and 20A include upstream-side
first branch flow path 10A and downstream-side first branch flow
path 20A. First electrolyzed water generator 100A is connected
between upstream-side first branch flow path 10A and
downstream-side first branch flow path 20A.
[0034] Second branch flow paths 10B and 20B include upstream-side
second branch flow path 10B and downstream-side second branch flow
path 20B. Second electrolyzed water generator 100B is connected
between upstream-side second branch flow path 10B and
downstream-side second branch flow path 20B.
[0035] Trunk flow path 15, upstream-side first branch flow path
10A, downstream-side first branch flow path 20A, upstream-side
second branch flow path 10B, and downstream-side second branch flow
path 20B are each a hollow rectangular tube made of acrylic
resin.
[0036] Electrolyzed water generation system 1000 is a branch
portion between trunk flow path 15 and upstream-side first branch
flow path 10A, and at a branch portion between trunk flow path 15
and upstream-side second branch flow path 10B, flow path change
mechanism V is provided. In the present exemplary embodiment, flow
path change mechanism V is a three-way valve that functions as a
flow path switching valve. In electrolyzed water generation system
1000 of the present exemplary embodiment, the raw water flowing
through trunk flow path 15 passes through flow path change
mechanism V and flows into (is supplied to) any one of
upstream-side first branch flow path 10A and upstream-side second
branch flow path 10B.
[0037] The raw water that has flowed into upstream-side first
branch flow path 10A flows into first electrolyzed water generator
100A. The raw water that has flowed into first electrolyzed water
generator 100A changes into electrolyzed water when passing through
first electrolyzed water generator 100A, and flows into
downstream-side first branch flow path 20A.
[0038] The raw water that has flowed into upstream-side second
branch flow path 10B flows into second electrolyzed water generator
100B. The raw water that has flowed into second electrolyzed water
generator 100B changes into electrolyzed water when passing through
second electrolyzed water generator 100B, and flows into
downstream-side second branch flow path 20B.
(Controller)
[0039] As shown in FIG. 1, electrolyzed water generation system
1000 includes controllers CA, CB, CC, and CD. Controller CA
controls first electrolyzed water generator 100A. Controller CB
controls second electrolyzed water generator 100B. Controller CC
controls flow path change mechanism V. Controller CD controls pump
P. In the present exemplary embodiment, controllers CA, CB, CC, and
CD are drawn as separate parts. However, controllers CA, CB, CC,
and CD may be a single controller that is formed of a single
integrally formed part.
[0040] Electrolyzed water generation system 1000 includes input
unit I operated by an operator. Input unit I transmits a command
signal to each of controllers CA, CB, CC, and CD based on the
operation of the operator. Controller CA and controller CB each has
sensor S, memory M, processor PR, and the like. In controllers CA
and CB, processor PR uses a program stored in memory M to generate
DC power DC from AC power AC. As a result, controller CA applies a
DC voltage to anode 1A (see FIG. 2) and cathode 1C (see FIG. 2) in
first electrolyzed water generator 100A. Controller CB applies a DC
voltage to anode 1A (see FIG. 2) and cathode 1C (see FIG. 2) in
second electrolyzed water generator 100B. Although not shown,
controller CC and controller CD each has a sensor, a memory, a
processor and the like.
[0041] Controllers CA and CB each receive a current, flowing
between anode 1A and cathode 1C, through resistor (r).
Consequently, controllers CA, CB each control a value of the
voltage applied between anode 1A and cathode 1C based on
information of a value of the current flowing between anode 1A and
cathode 1C, the value being detected by sensor S. Specifically,
controllers CA, CB each control the value of the voltage applied
between anode 1A and cathode 1C such that the value of the current
flowing between anode 1A and cathode 1C becomes a predetermined
value.
[0042] The concentration of electrolyzed water, for example, the
concentration of ozone water, is estimated to be proportional to
the value of the current flowing between anode 1A and cathode 1C.
Therefore, in order to maintain the concentration of usable
electrolyzed water at a constant value (including a substantially
constant value), controllers CA, CB each change the voltage applied
between anode 1A and cathode 1C such that the value of the current
flowing between anode 1A and cathode 1C is maintained at an almost
constant value.
[0043] For example, if first electrolyzed water generator 100A
continues to be used, the value of the current detected by sensor S
of controller CA may be lower than a predetermined value. In this
case, controller CA that continues to be used executes a control
for increasing the value of the voltage applied between anode 1A
and cathode 1C such that the value of the current flowing between
anode 1A and cathode 1C in first electrolyzed water generator 100A
increases to a predetermined value.
[0044] For example, if second electrolyzed water generator 100B
continues to be used, the value of the current detected by sensor S
of controller CB may be lower than a predetermined value. In this
case, controller CB that continues to be used executes a control
for increasing the value of the voltage applied between anode 1A
and cathode 1C such that the value of the current flowing between
anode 1A and cathode 1C in second electrolyzed water generator 100B
increases to a predetermined value.
[0045] Controller CA controls first electrolyzed water generator
100A based on the command signal received from input unit I.
Controller CB controls second electrolyzed water generator 100B
based on the command signal received from input unit I. Controller
CC controls flow path change mechanism V based on the command
signal received from input unit I. Controller CD controls pump P
based on the command signal received from input unit I.
[0046] In controllers CA, CB, CC, and CD, when at least one of
first electrolyzed water generator 100A and second electrolyzed
water generator 100B is filled with water, or when an abnormal
situation such as electrical connection occurs in electrolyzed
water generation system 1000, first electrolyzed water generator
100A and second electrolyzed water generator 100B are stopped.
Controllers CA, CB, CC, and CD perform the subsequent usual
processing unless such an abnormal situation occurs.
(Flow Path Change Mechanism)
[0047] Flow path change mechanism V shown in FIG. 1 is controlled
by controller CC to selectively form one of a first state where raw
water is guided from trunk flow path 15 to upstream-side first
branch flow path 10A and a second state where the raw water is
guided from trunk flow path 15 to upstream-side second branch flow
path 10B. That is, flow path change mechanism V is switched between
the first state and the second state. Although flow path change
mechanism V is one three-way valve, that is, a flow path switching
valve in the present exemplary embodiment, flow path change
mechanism V may be two open/close valves provided in upstream-side
first branch flow path 10A and upstream-side second branch flow
path 10B, respectively. In this case, controller CC controls
opening/closing operation of the two switching valves such that the
opening/closing operation of the two open/close valves becomes the
same as flow path switching operation of the flow path switching
valve.
(Structure of Electrolyzed Water Generator)
[0048] First electrolyzed water generator 100A and second
electrolyzed water generator 100B of the first exemplary embodiment
shown in FIG. 2 will be described. First electrolyzed water
generator 100A and second electrolyzed water generator 100B are
both shown as an example of a plurality of electrolyzed water
generators. Therefore, any one of the three or more electrolyzed
water generators may be selectively and sequentially controlled to
a generation state where electrolyzed water is generated.
[0049] First electrolyzed water generator 100A and second
electrolyzed water generator 100B both function as an ozone water
generator that generates ozone water as electrolyzed water. In the
present exemplary embodiment, first electrolyzed water generator
100A and second electrolyzed water generator 100B have the same
structure. However, first electrolyzed water generator 100A and
second electrolyzed water generator 100B may have different
structures from each other.
[0050] First electrolyzed water generator 100A and second
electrolyzed water generator 100B both include housing 101 and
layered structure 1 provided in housing 101. Housing 101 has
electrode case 102 and electrode case lid 103 that closes an
opening above electrode case 102.
(Electrode Case)
[0051] As shown in FIG. 2, electrode case 102 of first electrolyzed
water generator 100A and electrode case 102 of second electrolyzed
water generator 100B have the same structure. Electrode case 102 is
made of acrylic resin, for example. Electrode case 102 has a
container structure having an open top surface.
[0052] Upstream-side first branch flow path 10A is connected to a
side surface on one end side of electrode case 102 of first
electrolyzed water generator 100A. Downstream-side first branch
flow path 20A is connected to a side surface on the other end side
facing the side surface on one end side of electrode case 102 of
first electrolyzed water generator 100A. Upstream-side second
branch flow path 10B is connected to a side surface on one end side
of electrode case 102 of second electrolyzed water generator 100B.
Downstream-side second branch flow path 20B is connected to a side
surface on the other end side facing the side surface on one end
side of electrode case 102 of second electrolyzed water generator
100B. Electrode case 102 has in its inside a rib (not shown) that
supports layered structure 1.
[0053] A bottom surface of electrode case 102 has two through-holes
104, 105. Power supply shafts 106, 107 extend to the outside of
electrode case 102 via two through-holes 104, 105, respectively.
Wirings (not shown) extending from tips of power supply shafts 106,
107 of first electrolyzed water generator 100A are electrically
connected to controller CA. Wirings extending from power supply
shafts 106, 107 of second electrolyzed water generator 100B are
electrically connected to controller CB.
(Layered Structure)
[0054] As shown in FIGS. 2 and 3, first electrolyzed water
generator 100A and second electrolyzed water generator 100B each
contain identical layered structure 1. Layered structure 1 includes
power supply body 1S, anode 1A, cation exchange membrane 5, and
cathode 1C. Anode 1A is formed on one main surface of power supply
body 1S by a plasma CVD (Chemical Vapor Deposition) method. Cation
exchange membrane 5 is stacked on anode 1A, that is, on a surface
of one end of anode 1A. Cathode 1C is stacked on cation exchange
membrane 5, that is, on a surface of cation exchange membrane 5
opposite to a surface on which anode 1A is stacked.
[0055] As shown in FIG. 2, upstream-side first branch flow path 10A
is connected to an inlet port on the upstream side of first
electrolyzed water generator 100A. Downstream-side first branch
flow path 20A is connected to an outlet port on the downstream side
of first electrolyzed water generator 100A. First electrolyzed
water generator 100A is switched to either a first generation state
where first electrolyzed water is generated from raw water flowing
through upstream-side first branch flow path 10A or a first
non-generation state where the first electrolyzed water is not
generated. That is, first electrolyzed water generator 100A is
switched between the first generation state and the first
non-generation state.
[0056] As shown in FIG. 2, upstream-side second branch flow path
10B is connected to an inlet port on the upstream side of second
electrolyzed water generator 100B. Downstream-side second branch
flow path 20B is connected to an outlet port on the downstream side
of second electrolyzed water generator 100B. Second electrolyzed
water generator 100B is switched to either a second generation
state where second electrolyzed water is generated from raw water
flowing through second branch flow path 10B or a second
non-generation state where the second electrolyzed water is not
generated. That is, second electrolyzed water generator 100B is
switched between the second generation state and the second
non-generation state.
[0057] Layered structure 1 electrolyzes raw water to generate ozone
water as electrolyzed water. Layered structure 1 has, for example,
a thin plate shape having a size of 10 mm.times.50 mm.times.1.2 mm.
Layered structure 1 has a hole portion, more specifically, a groove
or a slit. As will be described in detail later, the hole portion
penetrates cathode 1C and cation exchange membrane 5 and is
configured such that an upper surface (front surface) of anode 1A,
that is, a surface of anode 1A facing cation exchange membrane 5 is
exposed on a penetrated bottom surface.
[0058] As may be inferred from the cross-sectional view of FIG. 2,
cathode 1C and cation exchange membrane 5 are arranged such that a
slit as cathode hole 1CTH of cathode 1C and a slit as membrane hole
5TH of cation exchange membrane 5 overlap each other in plan view.
Thus, the above-mentioned hole portion of layered structure 1
communicates from the flow path above cathode 1C to the upper
surface of anode 1A.
[0059] In each of first electrolyzed water generator 100A and
second electrolyzed water generator 100B of the present exemplary
embodiment, anode 1A and cation exchange membrane 5 are arranged so
as to be in contact with each other. Cation exchange membrane 5 and
cathode 1C are arranged in contact with each other. In other words,
cation exchange membrane 5 is provided between anode 1A and cathode
1C so as to be in contact with anode 1A, and cation exchange
membrane 5 is provided between anode 1A and cathode 1C so as to be
in contact with cathode 1C. However, anode 1A and cation exchange
membrane 5 may be spaced from each other. Cation exchange membrane
5 and cathode 1C may be provided to be spaced from each other.
(Power Supply Body)
[0060] Power supply body 1S shown in FIGS. 2 and 3 imparts a
positive charge to anode 1A of layered structure 1. Power supply
body 1S has, for example, a thin plate shape having a size of 10
mm.times.50 mm.times.0.5 mm. Shaft attachment piece 1SA is
configured by an extending portion of one edge of power supply body
1S. Power supply body 1S may be, for example, a boron-doped
conductive diamond material or titanium. Power supply body 1S is
supported by electrode case 102. Power supply shaft 106 pulled out
from shaft attachment piece 1SA is electrically connected to
controller CA or controller CB.
(Anode)
[0061] Anode 1A shown in FIGS. 2 and 3 receives positive charges
from controllers CA, CB, that is, the positive charge imparted from
power supply body 1 to generate ozone bubbles as electrolyzed
water. Anode 1A has, for example, a thin plate shape having a size
of 10 mm.times.50 mm.times.3 sm. Anode 1A is, for example, a
boron-doped conductive diamond film.
(Cation Exchange Membrane)
[0062] Cation exchange membrane 5 shown in FIGS. 2 and 3 is held in
a state of being sandwiched between anode 1A and cathode 1C.
Positive charges imparted from power supply body 15 move from anode
1A to cathode 1C. Cation exchange membrane 5 has, for example, a
thin plate shape having a size of 10 mm.times.50 mm.times.0.2 mm.
Cation exchange membrane 5 has slit-shaped membrane hole 5TH
penetrating from an upper surface of cation exchange membrane 5 to
a lower surface of cation exchange membrane 5 toward anode 1A. In
other words, membrane hole 5TH penetrates cation exchange membrane
5 such that the surface of anode 1A facing cation exchange membrane
5 is exposed.
[0063] A longitudinal direction of slit-shaped membrane hole 5TH is
a direction orthogonal to a longitudinal direction of cathode 1C.
The dimensions of slit-shaped membrane hole 5TH are, for example, 7
mm.times.1 mm.times.0.5 mm. Differing from the view, membrane holes
5TH are provided at ten positions on cation exchange membrane 5,
for example. Cation exchange membrane 5 is provided with a groove
or a cutout that forms gap C1 or gap C2 that connects
(communicates) adjacent membrane holes 5TH to each other. That is,
gap C1 and gap C2 are connected to membrane hole 5TH. The groove or
cutout may be a recess that is necessarily formed during the
manufacturing process.
(Cathode)
[0064] Cathode 1C shown in FIG. 2 and FIG. 3 receives a positive
charge that has passed through cation exchange membrane 5 and
generates hydrogen bubbles. Cathode 1C has, for example, a thin
plate shape having a size of 10 mm.times.50 mm.times.0.5 mm. Shaft
attachment piece 1SC is configured by an extending portion of one
edge of cathode 1C. Cathode 1C has slit-shaped cathode hole 1CTH
penetrating from an upper surface of cathode 1C to a lower surface
of cathode 1C. Cathode hole 1CTH penetrates cathode 1C so as to
communicate with membrane hole 5TH.
[0065] A longitudinal direction of slit-shaped cathode hole 1CTH is
a direction orthogonal to the longitudinal direction of cathode 1C.
The dimensions of slit-shaped cathode hole 1CTH are, for example, 7
mm.times.1 mm.times.0.5 mm. Differing from the view, cathode holes
1CTH are provided at ten positions on cation 1C, for example. High
electrical resistance material R which is a resin coating material
is applied to an inner peripheral surface of cathode hole 1CTH. An
electrical resistance value of high electrical resistance material
R is larger (higher) than the electrical resistance value of
cathode 1C. Cathode 1C is made of stainless steel, for example.
Power supply shaft 107 pulled out from shaft attachment piece 1SC
of cathode 1C is electrically connected to controller CA or
controller CB.
(Chemical Action)
[0066] As shown in FIG. 4, in each of first electrolyzed water
generator 100A and second electrolyzed water generator 100B, when
no voltage is applied to anode 1A and cathode 1C and raw water does
not flow, a chemical action does not substantially occur.
[0067] As shown in FIG. 5, when a voltage is applied to anode 1A
and cathode 1C, the following chemical action occurs.
[0068] At anode 1A
3H.sub.2O.fwdarw.O.sub.3+6H.sup.++6e.sup.-
2H.sub.2O.fwdarw.O.sub.2+4H.sup.++4e.sup.-
[0069] At cathode 1C
2H.sub.2O+2e.sup.-.fwdarw.H.sub.2+2OH.sup.-
[0070] That is, in each of first electrolyzed water generator 100A
and second electrolyzed water generator 100B, oxygen and ozone are
generated near anode 1A, and hydrogen is generated near cathode 1C.
Whether ozone is generated near anode 1A depends on the voltage
applied between anode 1A and cathode 1C. In the present exemplary
embodiment, it is assumed that at an interface between anode 1A and
cation exchange membrane 5, a voltage sufficient to generate ozone
is applied between anode 1A and cathode 1C. However, at the
interface between anode 1A and cation exchange membrane 5, a
voltage with which no ozone is generated may be applied between
anode 1A and cathode 1C. As an electrode for generating ozone, for
example, a lead dioxide electrode, a diamond electrode, a platinum
electrode, a tantalum oxide electrode, or the like may be used.
[0071] As shown in FIG. 6, when raw water continues to be supplied
to cation exchange membrane 5 in a state where no voltage is
applied between anode 1A and cathode 1C, cation exchange membrane 5
incorporates metal cations (M.sup.+) contained in the raw water and
releases hydrogen ions (H.sup.+) into the raw water. When hydrogen
ions (H.sup.+) are bound to each other, hydrogen (H.sub.2) is
generated. The metal cation (M.sup.+) is, for example, calcium ion
(Ca.sup.2+) or sodium ion (Na.sup.+).
[0072] Then, when a voltage is applied between anode 1A and cathode
1C, a chemical reaction:
2H.sub.2O+2e.sup.-+M.sup.2+.fwdarw.H.sub.2+M(OH).sub.2 occurs near
the interface between anode 1A and cation exchange membrane 5. That
is, a metal cation (for example, Ca.sup.2+ or Na.sup.+) contained
in the raw water is bound to a hydroxide ion (OH) near anode 1A to
generate a metal hydroxide M(OH).sub.2.
[0073] For example, when a metal cation (M.sup.2+) is a calcium ion
(Ca.sup.2+), carbonate ion (CO.sup.2-) and calcium ion (Ca.sup.2+)
in water are bound. A scale (CaC.sub.3) is generated by binding of
the carbonate ion (CO.sup.2-) and the calcium ion (Ca.sup.2+) in
water. Thus, as shown by two-dot chain lines in FIG. 6, the scale
(CaCO.sub.3) may adhere to inner peripheral surfaces of membrane
hole 5TH and cathode hole 1CTH near the interface between cathode
1C and cation exchange membrane 5. However, according to first
electrolyzed water generator 100A and second electrolyzed water
generator 100B of the present exemplary embodiment, due to the
presence of high electrical resistance material R described later,
the adhesion of the scale (CaCO.sub.3) to the inner peripheral
surfaces of membrane hole 5TH and cathode hole 1CTH is suppressed.
As a result, a decrease in ozone generation efficiency due to
narrowing of membrane hole 5TH and cathode hole 1CTH by the scale
(CaCO.sub.3) adhering to the inner peripheral surfaces of membrane
hole 5TH and cathode hole 1CTH is suppressed.
(Gap)
[0074] Anode 1A and cation exchange membrane 5 are in contact with
each other. This is because it is preferable to improve efficiency
of movement of the positive charges from anode 1A to cation
exchange membrane 5 in order to increase generation efficiency of
electrolyzed water. Therefore, ozone bubbles may be retained in a
small space between contact surfaces of anode 1A and cation
exchange membrane 5 where water does not flow. Thus, in the present
exemplary embodiment, gap C1 in which a flow of water occurs is
provided between anode 1A and cation exchange membrane 5 such that
the flow of water occurs between anode 1A and cation exchange
membrane 5. As a result, ozone present between the contact surface
of anode 1A and the contact surface of cation exchange membrane 5
is naturally mixed into water by a siphon action caused by a flow
of water passing through gap C1 in directions along the respective
contact surfaces of anode 1A and cation exchange membrane 5. That
is, gap C1 is a path through which water flows from one end of
cation exchange membrane 5 to the other end of cation exchange
membrane 5. Therefore, it is suppressed that ozone is retained
between anode 1A and cation exchange membrane 5. From the above, it
is possible to suppress an increase in the voltage applied between
anode 1A and cathode 1C, which is necessary for generating
electrolyzed water.
[0075] Cation exchange membrane 5 and cathode 1C are in contact
with each other. This is because it is preferable to improve
efficiency of movement of the positive charges from cation exchange
membrane 5 to cathode 1C in order to increase the generation
efficiency of electrolyzed water. Therefore, hydrogen bubbles may
be retained in a small space between contact surfaces of cation
exchange membrane 5 and cathode 1C where water does not flow. Thus,
in the present exemplary embodiment, gap C2 in which a flow of
water occurs is provided between cation exchange membrane 5 and
cathode 1C such that the flow of water occurs between cation
exchange membrane 5 and cathode 1C. As a result, hydrogen present
between the contact surface of cation exchange membrane 5 and the
contact surface of cathode 1C is naturally mixed into water by the
siphon action caused by a flow of water passing through gap C2 in a
direction parallel to the respective contact surfaces of cation
exchange membrane 5 and cathode 1C. That is, gap C2 is a path
through which water flows from one end of cation exchange membrane
5 to the other end of cation exchange membrane 5. Thus, it is
suppressed that hydrogen is retained between cation exchange
membrane 5 and cathode 1C. From the above, it is possible to
suppress an increase in the voltage applied between anode 1A and
cathode 1C, which is necessary for generating electrolyzed
water.
[0076] As shown in FIG. 7, gap C1 is a groove or a cutout provided
in a surface of cation exchange membrane 5 facing anode 1A.
However, gap C1 may be a groove or a cutout formed in a surface of
anode 1A facing cation exchange membrane 5. Gap C1 may be the
groove or the cutout formed in the surface of cation exchange
membrane 5 facing anode 1A and the groove or the cutout formed in
the surface of anode 1A facing cation exchange membrane 5. In other
words, gap C1 is a groove or a cutout formed in at least one of the
surface of cation exchange membrane 5 facing anode 1A and the
surface of anode 1A facing cation exchange membrane 5. Gap C1 may
be naturally formed between anode 1A and cation exchange membrane 5
during manufacturing.
[0077] Gap C1 is actually a large number of fine cutouts or grooves
formed in a non-woven fabric forming cation exchange membrane 5,
unlike the large groove or cutout as illustrated in the drawings.
The position and size of gap C1 are not limited as long as gap C1
has a portion where a flow of water occurs between anode 1A and
cation exchange membrane 5 and anode 1A and cation exchange
membrane 5 are in contact with each other.
[0078] As shown in FIG. 7, gap C2 is a groove or a cutout provided
in a surface of cation exchange membrane 5 facing cathode 1C.
However, gap C2 may be a groove or a cutout formed in a surface of
cathode 1C facing cation exchange membrane 5. Gap C2 may be the
groove or the cutout formed in the surface of cation exchange
membrane 5 facing cathode 1C and the groove or the cutout formed in
the surface of cathode 1C facing cation exchange membrane 5. In
other words, gap C2 is a groove or a cutout formed in at least one
of the surface of cation exchange membrane 5 facing cathode 1C and
the surface of cathode 1C facing cation exchange membrane 5. Gap C2
may be naturally formed between cathode 1C and cation exchange
membrane 5 during manufacturing.
[0079] Gap C2 is actually a large number of fine cutouts or grooves
formed in a non-woven fabric forming cation exchange membrane 5,
unlike the large groove or cutout as illustrated in the drawings.
The position and size of gap C2 are not limited as long as gap C2
has a portion where a flow of water occurs between cation exchange
membrane 5 and cathode 1C and cation exchange membrane 5 and
cathode 1C are in contact with each other.
[0080] As shown in FIG. 7, anode 1A and cathode 1C each have a flat
plate shape. Flat plate-shaped anode 1A, cation exchange membrane
5, and flat plate-shaped cathode 1C form (configure) layered
structure 1 in which these are stacked in this order. Cation
exchange membrane 5 has a plurality of membrane holes 5TH
penetrating in a thickness direction of cation exchange membrane 5.
Cathode 1C has a plurality of cathode holes 1CTH penetrating in a
thickness direction of cathode 1C and communicating with each of
the plurality of membrane holes 5TH. Therefore, a surface of anode
1A on a side of cation exchange membrane 5, inner surfaces of the
plurality of membrane holes 5TH, and inner surfaces of the
plurality of cathode holes 1CTH form a plurality of hole portions.
That is, the plurality of hole portions are configured such that
the surface of anode 1A on the side of cation exchange membrane 5
is the bottom surface and the inner surfaces of the plurality of
membrane holes 5TH and the inner surfaces of the plurality of
cathode holes 1CTH are the peripheral surfaces.
[0081] As shown in FIG. 7, gap C1 between anode 1A and cation
exchange membrane 5 communicates adjacent hole portions of the
plurality of hole portions, formed in the layered structure 1, with
each other. Thus, ozone present between anode 1A and cation
exchange membrane 5 efficiently mixes into the flow of water. Gap
C2 between cation exchange membrane 5 and cathode 1C communicates
adjacent hole portions of the plurality of hole portions, formed in
the layered structure 1, with each other. Thus, hydrogen present
between cation exchange membrane 5 and cathode 1C efficiently mixes
into water.
(High Electrical Resistance Material)
[0082] As can be seen from FIGS. 4 to 8, the inner peripheral
surface of cathode hole 1CTH is covered with high electrical
resistance material R having an electrical resistance value higher
than the electrical resistance value of cathode 1C. In other words,
high electrical resistance material R is provided in cathode hole
1CTH and has an electrical resistance value higher than the
electrical resistance value of cathode 1C. Thus, in the inner
peripheral surface of cathode hole 1CTH, force of attracting
cations contained in water is weakened. This suppresses the
retention of cations in cathode hole 1CTH. Thus, binding between
the cation retained on the inner peripheral surface of cathode hole
1CTH and an anion contained in water is suppressed. As a result,
generation of a scale due to the binding of cation and anion is
suppressed. Therefore, a decrease in the ability to generate
electrolyzed water due to retention of the scale in cathode hole
1CTH is suppressed.
[0083] In the present exemplary embodiment, high electrical
resistance material R may be configured by changing the inner
peripheral surface of stainless steel cathode hole 1CTH forming
cathode 1C by heating or a chemical reaction. The entire inner
peripheral surface of cathode hole 1CTH is preferably covered with
high electrical resistance material R. High electrical resistance
material R is preferably an insulating material.
[0084] In addition, of the contact surface between cathode 1C and
cation exchange membrane 5, a portion around the inner peripheral
surface of cathode hole 1CTH, for example, a portion of the lower
surface and the upper surface of cathode 1C may also be covered
with high electrical resistance material R. However, since cathode
1C and cation exchange membrane 5 are in contact with each other at
any position (portion), the cation can be transferred from cation
exchange membrane 5 to cathode 1C. According to this, the
generation of the scale is more reliably suppressed.
[0085] In addition, it is preferable that the entire inner
peripheral surface of each of the plurality of cathode holes 1CTH
be covered with high electrical resistance material R. According to
this, the generation efficiency of electrolyzed water is increased,
and the generation of the scale is more reliably suppressed.
[0086] High electrical resistance material R is a coating material
applied to cathode 1C. Specifically, high electrical resistance
material R is a coating material applied to cathode hole 1CTH
(inner peripheral surface of cathode 1C). Thus, high electrical
resistance material R easily adheres to the inner peripheral
surface of cathode 1C.
[0087] High electrical resistance material R is preferably an
insulating material. When high electrical resistance material R is
an insulating material, the generation of the scale is more
reliably suppressed.
[0088] In the present exemplary embodiment, cathode 1C is formed
(configured) of a stainless steel material, and high electrical
resistance material R is formed (configured) of a fluorine resin
material. Thus, both a value of adhesion strength between cathode
1C and the coating material and a required electrical resistance
value of the coating material can be set to desired values.
(Cathode and High Electrical Resistance Material of Another
Example)
[0089] As shown in FIG. 8, first electrolyzed water generator 100A
and second electrolyzed water generator 100B may include cathode 1C
of another example. Cathode 1C of the other example has a frame
shape. A lower surface of cathode 1C having a frame shape in the
other example is provided to be in contact with the upper surface
of cation exchange membrane 5. In this case, gap C1 and gap C2 may
not be provided in cation exchange membrane 5.
[0090] High electrical resistance material R is fitted into
frame-shaped cathode 1C so as to cover the inner peripheral surface
of frame-shaped cathode 1C. In other words, high electrical
resistance material R is provided on an inner periphery of
frame-shaped cathode 1C so as to be in contact with the inner
peripheral surface of frame-shaped cathode 1C. High electrical
resistance material R has a structure like a lattice window.
Specifically, high electrical resistance material R has an outer
shape of a plate-shaped member and has a plurality of communication
holes RTH that communicate with the plurality of membrane holes
5TH, respectively. That is, the plurality of communication holes
RTH penetrate high electrical resistance material R so as to
communicate with the plurality of membrane hole 5TH, respectively.
High electrical resistance material R has an electrical resistance
value higher than the electrical resistance value of the
cathode.
[0091] According to this, the inner peripheral surface of
frame-shaped cathode 1C and the inner peripheral surface of each of
the plurality of membrane holes 5TH of cation exchange membrane 5
are insulated by high electrical resistance material R. Therefore,
a possibility (probability) of scale generation near membrane hole
5TH is reduced. Below membrane hole 5TH, ozone generated on the
upper surface of anode 1A exposed to water is mixed into water
flowing above cathode 1C through the plurality of communication
holes RTH.
(Switching Control of System)
[0092] As shown in FIG. 9, controller CD drives (ON) pump P to feed
raw water into trunk flow path 15. Flow path change mechanism V is
selectively switched to either the first state or the second state
by controller CC. In the present exemplary embodiment, the first
state is a state where flow path change mechanism V guides
(supplies) the raw water from trunk flow path 15 to upstream-side
first branch flow path 10A. The second state is a state where flow
path change mechanism V guides (supplies) the raw water from trunk
flow path 15 to upstream-side second branch flow path 10B.
[0093] First, controller CC switches flow path change mechanism V
from a closed state to the first state. Consequently, the raw water
is guided from trunk flow path 15 to upstream-side first branch
flow path 10A. After that, the raw water is supplied to first
electrolyzed water generator 100A.
[0094] Next, at any time during a period in which flow path change
mechanism V is in the first state, controller CA executes control
in which first electrolyzed water generator 100A generates
electrolyzed water, that is, control in which first electrolyzed
water generator 100A is brought into the first generation state.
That is, a voltage is applied between anode 1A and cathode 1C of
first electrolyzed water generator 100A. In first electrolyzed
water generator 100A, electrolyzed water is generated by applying
(ON) the voltage between anode 1A and cathode 1C. In other words,
controller CA applies the voltage between anode 1A and cathode 1C
of first electrolyzed water generator 100A and thereby performs
control to switch first electrolyzed water generator 100A from the
first non-generation state to the first generation state.
[0095] When flow path change mechanism V is in the first state,
controller CB executes control in which second electrolyzed water
generator 100B does not generate electrolyzed water, that is,
control in which second electrolyzed water generator 100B is
brought into the second non-generation state. That is, no voltage
is applied between anode 1A and cathode 1C of second electrolyzed
water generator 100B. In other words, second electrolyzed water
generator 100B is in a stopped (OFF) state.
[0096] After that, controller CD executes control to stop pump P,
and controller CC switches flow path change mechanism V from the
first state to the closed state. At this time, in first
electrolyzed water generator 100A, controller CA does not apply a
voltage between cathode 1C and anode 1A. In second electrolyzed
water generator 100B, controller CB does not apply a voltage
between cathode 1C and anode 1A.
[0097] Next, while controller CD is executing control to drive pump
P, controller CC switches flow path change mechanism V from the
closed state to the second state. Consequently, the raw water is
guided from trunk flow path 15 to upstream-side second branch flow
path 10B. After that, the raw water is supplied to second
electrolyzed water generator 100B.
[0098] When flow path change mechanism V is in the second state,
controller CA executes control in which first electrolyzed water
generator 100A does not generate electrolyzed water, that is,
control in which first electrolyzed water generator 100A is brought
into the first non-generation state. That is, no voltage is applied
between anode 1A and cathode 1C of first electrolyzed water
generator 100A. In other words, first electrolyzed water generator
100A is in a stopped (OFF) state.
[0099] Next, at any time during a period in which flow path change
mechanism V is in the second state, controller CB executes control
in which second electrolyzed water generator 100B generates
electrolyzed water, that is, control in which second electrolyzed
water generator 100B is brought into the second generation state.
That is, a voltage is applied between anode 1A and cathode 1C of
second electrolyzed water generator 100B. In second electrolyzed
water generator 100B, electrolyzed water is generated by applying
(ON) the voltage between anode 1A and cathode 1C. In other words,
controller CB applies the voltage between anode 1A and cathode 1C
of second electrolyzed water generator 100B and thereby performs
control to switch second electrolyzed water generator 100B from the
second non-generation state to the second generation state.
[0100] Generally, when first electrolyzed water generator 100A and
second electrolyzed water generator 100B are continuously used, the
scale adheres to cathode 1C or the like due to an increase in pH of
electrolyzed water. The scales include what are called calcium
scales, magnesium scales, and hardness component scales. Examples
of these scales include calcium carbonate, magnesium carbonate,
calcium sulfate, magnesium hydroxide, and calcium phosphate, and
iron hydroxide and iron oxide as examples of scales called iron
salt scales (iron rust).
[0101] When the scale is generated, the value of the current
flowing between anode 1A and cathode 1C decreases. In this case,
controller CA or CB executes control to increase the value of the
voltage applied between anode 1A and cathode 1C. Therefore, if
first electrolyzed water generator 100A is continuously used, the
generation efficiency of electrolyzed water by first electrolyzed
water generator 100A decreases. On the other hand, if second
electrolyzed water generator 100B is continuously used, the
generation efficiency of electrolyzed water by second electrolyzed
water generator 100B decreases.
[0102] From the above, in order to suppress the scale generation,
it is conceivable to shorten a period of continuous use of each of
first electrolyzed water generator 100A and second electrolyzed
water generator 100B. Thus, the electrolyzed water generator that
generates electrolyzed water and the electrolyzed water generator
that does not generate electrolyzed water are switched such that
the period of use of each electrolyzed water generator is divided.
According to this, the period of use of each of first electrolyzed
water generator 100A and second electrolyzed water generator 100B
is shortened. On the other hand, electrolyzed water generation
system 1000 as a whole continuously generates electrolyzed water.
As a result, the increase in the voltage applied between anode 1A
and cathode 1C is suppressed in order to obtain electrolyzed water
of a desired concentration, and the ability to generate
electrolyzed water is maintained.
(Intermittent Operation Control of System)
[0103] As shown in FIG. 9, controller CA of first electrolyzed
water generator 100A and controller CB of second electrolyzed water
generator 100B both intermittently apply the voltage between anode
1A and cathode 1C. Thus, while the application of the voltage
between anode 1A and cathode 1C is stopped, ozone retained between
anode 1A and cation exchange membrane 5 flows out into water, and
hydrogen retained between cation exchange membrane 5 and cathode 1C
flows out into water. As a result, retention of ozone between anode
1A and cation exchange membrane 5 is suppressed, and retention of
hydrogen between cation exchange membrane 5 and cathode 1C is
suppressed.
[0104] As shown in FIG. 9, controllers CA, CB, CC, CD control pump
P and flow path change mechanism V. Consequently, raw water is
guided to electrolyzed water generators 100A, 100B not only during
the period in which the voltage is applied between anode 1A and
cathode 1C but also during a portion of the period in which the
application of the voltage is stopped. More specifically, in
addition to the period in which the voltage is applied between
anode 1A and cathode 1C, during a predetermined period before and
after the period in which the voltage is applied between anode 1A
and cathode 1C, the raw water is guided to electrolyzed water
generators 100A, 100B. In other words, the raw water is supplied to
electrolyzed water generators 100A, 100B during the period in which
no voltage is applied between anode 1A and cathode 1C. Thus,
retention of ozone between anode 1A and cation exchange membrane 5
is more reliably suppressed, and retention of hydrogen between
cation exchange membrane 5 and cathode 1C is more reliably
suppressed. Controller CD may control switching between drive (ON)
and stop (OFF) of pump P so as to deliver the raw water to trunk
flow path 15 in synchronization with switching between application
(ON) and stop (OFF) of the voltage.
(Operation of Electrolyzed Water Generation System)
[0105] An operator operates input unit I and transmits a command
signal from input unit I to controllers CA, CB, CC, CD.
Consequently, first, pump P is driven, and raw water is fed to
first electrolyzed water generator 100A. Then, a voltage is applied
between anode 1A and cathode 1C of first electrolyzed water
generator 100A. Consequently, electrolyzed water is generated in
first electrolyzed water generator 100A. In the present exemplary
embodiment, ozone bubbles are generated near an interface between
cation exchange membrane 5 and anode 1A in first electrolyzed water
generator 100A. Hydrogen is generated near an interface between
cation exchange membrane 5 and cathode 1C in first electrolyzed
water generator 100A. Ozone bubbles and hydrogen bubbles are
dissolved in the raw water. As a result, ozone water is generated
as electrolyzed water.
[0106] As time passes in a state where the voltage is applied
between anode 1A and cathode 1C of first electrolyzed water
generator 100A, ozone bubbles are retained in an inevitable gap
between anode 1A and cation exchange membrane 5, that is, a gap
closed to the extent that water does not now. The inevitable gap is
so small that it cannot be shown. Ozone bubbles retained in the
inevitable gap function as an insulator between anode 1A and
cathode 1C. However, ozone retained in the inevitable gap between
anode 1A and cation exchange membrane 5 is sucked into water by the
siphon action caused by a flow of water flowing through gap C1 and
flows out from first electrolyzed water generator 100A to
downstream-side first branch flow path 20A.
[0107] As time passes in the state where the voltage is applied
between anode 1A and cathode 1C of first electrolyzed water
generator 100A, hydrogen bubbles are retained in an inevitable gap
between cation exchange membrane 5 and cathode 1C. The inevitable
gap is so small that it cannot be shown. Hydrogen bubbles retained
in the inevitable gap function as an insulator between anode 1A and
cathode 1C. However, hydrogen retained in the inevitable gap
between cathode 1C and cation exchange membrane 5 is sucked into
water by the siphon action caused by a flow of water flowing
through gap C2 and flows out from first electrolyzed water
generator 100A to downstream-side first branch flow path 20A.
[0108] In the above case, hydroxide ion concentration increases in
a hole portion formed by membrane hole 5TH, cathode hole 1CTH (or
communication hole RTH), and the surface of anode 1A of layered
structure 1 of first electrolyzed water generator 100A, that is, a
slit. As a result, hydroxide salt (scale) is temporarily retained
in the hole portion. In the present exemplary embodiment, the inner
peripheral surface of cathode hole 1CTH is covered with high
electrical resistance material R. Thus, the generated scale is
mixed into electrolyzed water without adhering to cathode hole
1CTH, and flows out from first electrolyzed water generator 100A to
downstream-side first branch flow path 20A together with the
electrolyzed water.
[0109] When raw water is fed to first electrolyzed water generator
100A, the raw water is not fed to second electrolyzed water
generator 100B. Thus, it is suppressed that metal cations contained
in the raw water are accumulated on cation exchange membrane 5 of
second electrolyzed water generator 100B. For example, exchange
between hydrogen ions (H.sup.+) in cation exchange membrane 5 of
second electrolyzed water generator 100B and calcium ions
(Ca.sup.2+) in the raw water is suppressed.
[0110] When a predetermined time elapses after the voltage is
applied between anode 1A and cathode 1C of first electrolyzed water
generator 100A, the application of the voltage between anode 1A and
cathode 1C of first electrolyzed water generator 100A is stopped.
As a result, generation of ozone between anode 1A and cation
exchange membrane 5 and generation of hydrogen between cation
exchange membrane 5 and cathode 1C are stopped. After that, pump P
continues to be driven only for a predetermined period. As a
result, the raw water is fed to first electrolyzed water generator
100A in a state where the application of the voltage between anode
1A and cathode 1C of first electrolyzed water generator 100A is
stopped. Consequently, most ozone bubbles retained between anode 1A
and cation exchange membrane 5 flow out into the raw water, and
then most ozone bubbles are (almost completely) discharged from
first electrolyzed water generator 100A together with the raw
water. On the other hand, most hydrogen bubbles retained between
cation exchange membrane 5 and cathode 1C flow out into the raw
water, and then most hydrogen bubbles are (almost completely)
discharged from first electrolyzed water generator 100A together
with the raw water.
[0111] Pump P stops when a predetermined time elapses after the
application of the voltage between anode 1A and cathode 1C of first
electrolyzed water generator 100A is stopped. This prevents the raw
water from being fed to first electrolyzed water generator 100A.
Therefore, hydroxide ions (OH.sup.-) are almost completely
discharged from first electrolyzed water generator 100A. As a
result, alkalinity of the raw water inside first electrolyzed water
generator 100A is reduced. Therefore, the scale generation in first
electrolyzed water generator 100A is suppressed.
[0112] After that, while controller CD continues to execute the
control to drive pump P, controller CC executes control to switch
flow path change mechanism V, so that the raw water that has been
fed to first electrolyzed water generator 100A is fed to second
electrolyzed water generator 100B. Then, a voltage is applied
between anode 1A and cathode 1C of second electrolyzed water
generator 100B. Consequently, electrolyzed water is generated in
second electrolyzed water generator 100B. In the present exemplary
embodiment, ozone bubbles are generated near the interface between
cation exchange membrane 5 and anode 1A. Hydrogen is generated near
an interface between cation exchange membrane 5 and cathode 1C in
second electrolyzed water generator 100B. Ozone bubbles and
hydrogen bubbles are dissolved in the raw water. As a result, ozone
water is generated as electrolyzed water.
[0113] As time passes in a state where the voltage is applied
between anode 1A and cathode 1C of second electrolyzed water
generator 100B, ozone bubbles are retained in an inevitable gap
between anode 1A and cation exchange membrane 5, that is, a gap
closed to the extent that water does not flow. The inevitable gap
is so small that it cannot be shown. Ozone bubbles retained in the
inevitable gap function as an insulator between anode 1A and
cathode 1C. However, ozone retained in the inevitable gap between
anode 1A and cation exchange membrane 5 is sucked into water by the
siphon action caused by a flow of water flowing through gap C1 and
flows out from second electrolyzed water generator 100B to
downstream-side second branch flow path 20B.
[0114] As time passes in the state where the voltage is applied
between anode 1A and cathode 1C of second electrolyzed water
generator 100B, hydrogen bubbles are retained in an inevitable gap
between cation exchange membrane 5 and cathode 1C. The inevitable
gap is so small that it cannot be shown. Hydrogen bubbles retained
in the inevitable gap function as an insulator between anode 1A and
cathode 1C. However, hydrogen retained in the inevitable gap
between cathode 1C and cation exchange membrane 5 is sucked into
water by the siphon action caused by a flow of water flowing
through gap C2 and flows out from second electrolyzed water
generator 100B to downstream-side second branch flow path 20B.
[0115] In the above case, hydroxide ion concentration increases in
a hole portion formed by membrane hole 5TH, cathode hole 1CTH (or
communication hole RTH), and the surface of anode 1A of layered
structure 1 of second electrolyzed water generator 100B, that is, a
slit. As a result, hydroxide salt (scale) is temporarily retained
in the hole portion. In the present exemplary embodiment, the inner
peripheral surface of cathode hole 1CTH is covered with high
electrical resistance material R. Thus, the generated scale is
mixed into electrolyzed water without adhering to cathode hole
1CTH, and flows out from second electrolyzed water generator 100B
to downstream-side second branch flow path 20B together with the
electrolyzed water.
[0116] When raw water is fed to second electrolyzed water generator
100B, the raw water is not fed to first electrolyzed water
generator 100A. Thus, it is suppressed that metal cations contained
in the raw water are accumulated on cation exchange membrane 5 of
first electrolyzed water generator 100A. For example, exchange
between hydrogen ions (H.sup.+) in cation exchange membrane 5 of
first electrolyzed water generator 100A and calcium ions
(Ca.sup.2+) in the raw water is suppressed.
[0117] When a predetermined time elapses after the voltage is
applied between anode 1A and cathode 1C of second electrolyzed
water generator 100B, the application of the voltage between anode
1A and cathode 1C of second electrolyzed water generator 100B is
stopped. As a result, generation of ozone between anode 1A and
cation exchange membrane 5 and generation of hydrogen between
cation exchange membrane 5 and cathode 1C are stopped. After that,
pump P continues to be driven only for a predetermined period. As a
result, raw water is fed to second electrolyzed water generator
100B in a state where the application of the voltage between anode
1A and cathode 1C of second electrolyzed water generator 100B is
stopped. Consequently, most ozone bubbles retained between anode 1A
and cation exchange membrane 5 flow out into the raw water, and
then most ozone bubbles are (almost completely) discharged from
second electrolyzed water generator 100B together with the raw
water. On the other hand, most hydrogen bubbles retained between
cation exchange membrane 5 and cathode 1C flow out into the raw
water, and then most hydrogen bubbles are (almost completely)
discharged from second electrolyzed water generator 100B together
with the raw water.
[0118] Pump P stops when a predetermined time elapses after the
application of the voltage between anode 1A and cathode 1C of
second electrolyzed water generator 100B is stopped. This prevents
raw water from being fed to second electrolyzed water generator
100B. Therefore, hydroxide ions (OH) are almost completely
discharged from second electrolyzed water generator 100B. As a
result, alkalinity of the raw water inside second electrolyzed
water generator 100B is reduced. The scale generation in second
electrolyzed water generator 100B is suppressed.
[0119] After that, while controller CD continues to execute the
control to drive pump P, controller CC executes control to switch
flow path change mechanism V, so that the raw water that has been
fed to second electrolyzed water generator 100B is fed to first
electrolyzed water generator 100A. Then, a voltage is applied again
between anode 1A and cathode 1C of first electrolyzed water
generator 100A.
[0120] Electrolyzed water generation system 1000 of the present
exemplary embodiment as described above is used for a place where
only ozone water for sterilization is used without using ordinary
water, for example, for flushing water of a toilet bowl.
Second Exemplary Embodiment
[0121] Electrolyzed water generation system 1000 of the present
exemplary embodiment is almost the same as electrolyzed water
generation system 1000 of first exemplary embodiment. Hereinafter,
differences between electrolyzed water generation system 1000 of
the present exemplary embodiment and electrolyzed water generation
system 1000 of the first exemplary embodiment will be mainly
described. Electrolyzed water generator 100A of the present
exemplary embodiment is assumed to be the same as first
electrolyzed water generator 100A and second electrolyzed water
generator 100B of the first exemplary embodiment.
[0122] However, electrolyzed water generator 100A of the present
exemplary embodiment may be different from first electrolyzed water
generator 100A and second electrolyzed water generator 100B of the
first exemplary embodiment. For example, in electrolyzed water
generator 100A, an ion exchange membrane and a cathode formed of a
wire mesh may be wound or bonded in this order by pressure welding
on an outside of an anode formed of a platinum wire mesh.
[0123] As shown in FIG. 10, electrolyzed water generation system
1000 includes trunk flow path 15, upstream-side first branch flow
path 10A, downstream-side first branch flow path 20A, electrolyzed
water generator 100A, upstream-side second branch flow path 10B,
downstream-side second branch flow path 20B, and flow path change
mechanism V.
[0124] Flow path change mechanism V includes open/close valve V1
and open/close valve V2. In the present exemplary embodiment,
open/close valve V1 is provided (connected) to upstream-side first
branch flow path 10A. Open/close valve V2 is provided (connected)
to upstream-side second branch flow path 10B. Instead of open/close
valve V1 and open/close valve V2, a three-way valve as the flow
path switching valve of the first exemplary embodiment may be
provided at a branch portion between trunk flow path 15 and each of
upstream-side first branch flow path 10A and upstream-side second
branch flow path 10B.
[0125] As shown in FIG. 10, trunk flow path 15 receives raw water
delivered by pump P. That is, the raw water is supplied from pump P
to trunk flow path 15.
[0126] Upstream-side first branch flow path 10A branches from trunk
flow path 15.
[0127] Electrolyzed water generator 100A includes anode 1A, cathode
1C, and cation exchange membrane 5 provided between anode 1A and
cathode 1C. Electrolyzed water generator 100A is connected to
upstream-side first branch flow path 10A and downstream-side first
branch flow path 20A.
[0128] Electrolyzed water generator 100A is switched to either a
generation state where electrolyzed water is generated from raw
water flowing through upstream-side first branch flow path 10A or a
non-generation state where the electrolyzed water is not generated.
That is, electrolyzed water generator 100A is switched between the
generation state and the non-generation state.
[0129] Upstream-side second branch flow path 10B branches from
trunk flow path 15 and guides raw water, flowing through trunk flow
path 15, to the downstream of trunk flow path 15. Open/close valves
V1, V2 are changed to either one of a first state and a second
state by controller C. The first state is a state where open/close
valve V1 is opened and open/close valve V2 is closed, and a state
where the raw water is guided from trunk flow path 15 to
upstream-side first branch flow path 10A. The second state is a
state where open/close valve V1 is closed and open/close valve V2
is opened, and a state where the raw water is guided from trunk
flow path 15 to upstream-side second branch flow path 10B.
[0130] According to the above configuration, when no voltage is
applied between anode 1A and cathode 1C, open/close valves V1, V2
can be switched to the second state such that the raw water is not
supplied to cation exchange membrane 5. That is, controller C
brings open/close valve V1 into a closed state and brings
open/close valve V2 into an open state. This can suppress that
cation exchange membrane 5 in electrolyzed water generator 100A
incorporates cations contained in the raw water.
[0131] Thus, it is suppressed that when electrolyzed water
generator 100A is generating electrolyzed water, that is, when a
voltage is applied between anode 1A and cathode 1C, the cations
incorporated into cation exchange membrane 5 are released into
electrolyzed water. As a result, scale generation due to the
release of cations from cation exchange membrane 5 to the
electrolyzed water is suppressed.
[0132] When electrolyzed water generator 100A is not generating
electrolyzed water, water that is not electrolyzed water can be
taken out from second branch flow path 20B. Therefore, when
electrolyzed water generator 100A is not generating electrolyzed
water, it is possible to use water that is not electrolyzed water,
for example, water that is not ozone water, while suppressing scale
generation.
[0133] As shown in FIG. 10, electrolyzed water generation system
1000 includes purification device 200. Purification device 200 is
connected between upstream-side second branch flow path 10B and
downstream-side second branch flow path 20B and causes the raw
water as purified water, flowing through upstream-side second
branch flow path 10B, to flow out the downstream of second branch
flow path 20B. That is, purification device 200 generates purified
water from the raw water flowing through upstream-side second
branch flow path 10B. Thus, when electrolyzed water generator 100A
does not generate electrolyzed water, purified water can be used
instead of the raw water. Purification device 200 may not be
provided.
[0134] Electrolyzed water generation system 1000 of the present
exemplary embodiment as described above can be used for tap water
used in domestic kitchens. In this case, while an inner surface of
a kitchen sink can be sterilized and washed with ozone water, tap
water not containing ozone can be used for washing dishes and the
like.
(Electrolyzed Water Generation System of Another Example)
[0135] As shown in FIG. 11, electrolyzed water generation system
1000 of another example of the second exemplary embodiment includes
purification device 200. Purification device 200 is connected to
trunk flow path 15. Purification device 200 causes raw water as
purified water, flowing through trunk flow path 15, to flow out the
downstream of trunk flow path 15. That is, purification device 200
generates purified water from the raw water flowing through trunk
flow path 15. Purification device 200 may not be provided.
[0136] In electrolyzed water generation system 1000 of the other
example, electrolyzed water generator 100A generates electrolyzed
water from purified water instead of raw water. Thus, the
possibility of foreign matters entering the inside of electrolyzed
water generator 100A is reduced. When electrolyzed water generator
100A does not generate electrolyzed water, purified water can be
used instead of the raw water.
[0137] Ozone generation efficiency will be compared with reference
to FIGS. 12 and 13. FIG. 12 and FIG. 13 are graphs for comparing a
form of reduction in the ability to generate ozone water between a
case where ozone is continuously generated and a case where ozone
is intermittently generated, in one electrolyzed water generator,
under a condition that a total time of ozone generation is the
same. The ozone water being continuously generated indicates that a
voltage is continuously applied between anode 1A and cathode 1C of
electrolyzed water generator 100A. The ozone water being
intermittently generated indicates that a voltage is intermittently
applied between anode 1A and cathode 1C of electrolyzed water
generator 100A.
[0138] FIG. 12 shows a relationship between time and voltage in
electrolyzed water generator 100A in a case where pump P is in an
ON state and open/close valve V1 is in the open state when
electrodes (A, 1C) are turned off. FIG. 12 also shows a
relationship between time and voltage in electrolyzed water
generator 100A in a case where pump P is in an OFF state or the ON
state and open/close valve V1 is in the closed state when
electrodes (A, 1C) are turned off.
[0139] FIG. 13 shows a relationship between time and an amount of
ozone generation in electrolyzed water generator 100A in the case
where pump P is in the ON state and open/close valve V1 is in the
open state when electrodes (1A 1C) are turned off. FIG. 13 also
shows a relationship between time and the amount of ozone
generation in electrolyzed water generator 100A in the case where
pump P is in the OFF state or the ON state and open/close valve V1
is in the closed state when electrodes (A, 1C) are turned off.
[0140] In FIG. 12 and FIG. 13. "when electrodes (A, 1C) are turned
off" means a state where no voltage is applied between anode 1A and
cathode 1C of electrolyzed water generator 100A. "Pump P is in the
ON state" indicates a state where raw water is flowing through
trunk flow path 15 by driving pump P. "Open/close valve V1 is in
the open state" indicates a state where the raw water is flowing
into electrolyzed water generator 100A by opening open/close valve
V1. "Open/close valve V1 is in the closed state" indicates a state
where the raw water is not flowing into electrolyzed water
generator 100A by closing open/close valve V1.
[0141] In FIG. 12, in a case where open/close valve V1 is in the
open state when electrodes (1A, 10) are turned off, compared with a
case where open/close valve V1 is in the closed state when
electrodes (A, 10) are turned off, the voltage applied between
anode 1A and cathode 1C increases in a shorter time. In other
words, from FIG. 12, it is found that when no voltage is applied
between anode 1A and cathode 1C, if the supply of the raw water to
electrolyzed water generator 100A is stopped, an increase in the
voltage applied between anode 1A and cathode 1C, which is necessary
for generating a desired concentration of ozone is suppressed. This
is because scale generation near cathode 1C when no voltage is
applied between anode 1A and cathode 1C is suppressed.
[0142] In FIG. 13, in the case where open/close valve V1 is in the
open state when electrodes (1A, 1C) are turned off, compared with
the case where open/close valve V1 is in the closed state when the
electrodes are turned off, the concentration of ozone obtained
downstream of electrolyzed water generator 100A decreases in a
shorter time. In other words, from FIG. 13, it is found that when
no voltage is applied between anode 1A and cathode 1C, if the
supply of the raw water to electrolyzed water generator 100A is
stopped, a decrease in ozone concentration is suppressed. This is
because scale generation near cathode 1C when no voltage is applied
between anode 1A and cathode 1C is suppressed.
[0143] As shown in FIG. 14, cation exchange membrane 5 of
electrolyzed water generator 100A of the other example has a
sulfonate group (--SO.sub.3H). As shown in FIG. 15, when no voltage
is applied between anode 1A and cathode 1C, cation exchange
membrane 5 accepts metal cations (Ca.sup.2+, Na.sup.+) in water and
releases hydrogen ions (H.sup.+) into water. That is, the cation is
replaced.
[0144] As shown in FIG. 15, in first electrolyzed water generator
100A of the other example, anode 1A, cation exchange membrane 5,
and cathode 1C may be arranged apart from each other instead of the
layered structure. Anode 1A and cathode 1C may have a mesh shape
instead of the flat plate shape. In first electrolyzed water
generator 100A of the other example, ozone may not be generated,
but hydrogen and oxygen may be generated in water.
[0145] As shown in FIG. 16, immediately after the voltage is
applied between anode 1A and cathode 1C, water (H.sub.2O) is
decomposed into a hydroxyl group (OH.sup.-) and a hydrogen ion
(H.sup.+) near anode 1A. As a result, cation exchange membrane 5
incorporates hydrogen ions (H.sup.+) and releases metal cations
(Ca.sup.2+, Na.sup.+) into water. Hydrogen (H.sub.2) is generated
near cathode 1C. Thus, in the state shown in FIG. 16, the
concentration of metal cations (Ca.sup.2+, Na.sup.+) in water
increases, and the pH of water rises.
[0146] As shown in FIG. 17, when the state where the voltage is
applied between anode 1A and cathode 1C is continued, the release
of metal cations (Ca.sup.2+, Na.sup.+) into water is stopped. In
the state shown in FIG. 17, the concentration of metal cations
(Ca.sup.2+, Na.sup.+) in water decreases, and the pH of water
decreases.
[0147] Also in the case of using electrolyzed water generator 100A
of the other example shown in FIGS. 14 to 17, similarly to first
electrolyzed water generator 100A and second electrolyzed water
generator 100B of the first exemplary embodiment, scale generation
is suppressed. Specifically, as in the first present exemplary
embodiment described above, scale generation due to the
incorporation of metal cations (Ca.sup.2+, Na.sup.+) in cation
exchange membrane 5 contained in flowing water is suppressed.
[0148] Hereinafter, characteristic configurations of electrolyzed
water generators 100A, 100B and electrolyzed water generation
system 1000 of the exemplary embodiment and effects obtained
thereby will be described.
[0149] (1) Electrolyzed water generators 100A, 100B include anode
1A, cathode 1C, and cation exchange membrane 5 provided between
anode 1A and cathode 1C so as to be in contact with at least one of
anode 1A and cathode 1C. Gaps C1, C2 in which a flow of water
occurs are present between cation exchange membrane 5 and at least
one of anode 1A and cathode 1C.
[0150] According to this, at least one of ozone present between
anode 1A and cation exchange membrane 5 and hydrogen present
between cation exchange membrane 5 and cathode 1C is naturally
mixed into water by the siphon action caused by the flow of water
passing through at least one of gap C1 between anode 1A and cation
exchange membrane 5 and gap C2 between cation exchange membrane 5
and cathode 1C. Thus, at least one of retention of ozone between
anode 1A and cation exchange membrane 5 and retention of hydrogen
between cation exchange membrane 5 and cathode 1C is suppressed. As
a result, the increase in the voltage applied between anode 1A and
cathode 1C, which is necessary for generating electrolyzed water is
suppressed.
[0151] (2) Gaps C1, C2 may include a groove or a cutout provided in
at least one of the surface of cation exchange membrane 5 facing at
least one of anode 1A and cathode 1C and the surface of at least
one of anode 1A and cathode 1C facing cation exchange membrane
5.
[0152] According to this, gaps C1, C2 can be easily formed.
[0153] (3) In electrolyzed water generators 100A, 100B, cation
exchange membrane 5 is provided in contact with anode 1A and
cathode 1C. Cation exchange membrane 5 is provided with membrane
hole 5TH penetrating cation exchange membrane 5 so that the surface
of anode 1A facing cation exchange membrane 5 is exposed. Cathode
1C is provided with cathode hole 1CTH penetrating cathode 1C so as
to communicate with membrane hole 5TH. Cathode hole 1CTH of cathode
1C is provided with high electrical resistance material R having an
electrical resistance value higher than the electrical resistance
value of cathode 1C.
[0154] According to the above configuration, in the inner
peripheral surface of cathode hole 1CTH, the force of attracting
cations contained in water is weakened. This suppresses the
retention of cations in cathode hole 1CTH. Thus, binding between
the cation retained on the inner peripheral surface of cathode hole
1CTH and the anion contained in water is suppressed. As a result,
generation of a scale due to the binding of cation and anion is
suppressed. Therefore, the decrease in the ability to generate
electrolyzed water due to retention of the scale in cathode hole
1CTH is suppressed.
[0155] (4) Gaps C1, C2 are paths through which water flows from one
end of cation exchange membrane 5 to the other end of cation
exchange membrane 5.
[0156] According to this, at least one of retention of ozone
between anode 1A and cation exchange membrane 5 and retention of
hydrogen between cation exchange membrane 5 and cathode 1C is
suppressed. As a result, the increase in the voltage applied
between anode 1A and cathode 1C, which is necessary for generating
electrolyzed water is suppressed.
[0157] (5) High electrical resistance material R may be a coating
material applied to cathode hole 1CTH.
[0158] According to this, high electrical resistance material R
easily adheres to cathode hole 1CTH.
[0159] (6) Electrolyzed water generators 100A, 100B include anode
1A, cation exchange membrane 5 provided in contact with anode 1A,
cathode 1C provided in contact with cation exchange membrane 5 and
having a frame shape, and high electrical resistance material R
provided on an inner periphery of the frame shape so as to be in
contact with an inner peripheral surface of the frame shape and
having an electrical resistance value higher than the electrical
resistance value of cathode 1C. Cation exchange membrane 5 is
provided with membrane hole 5TH penetrating cation exchange
membrane 5 so that the surface of anode 1A facing cation exchange
membrane 5 is exposed. High electrical resistance material R is
provided with communication hole RTH penetrating high electrical
resistance material R such that high electrical resistance material
R communicates with membrane hole 5TH.
[0160] According to this, the decrease in the ability to generate
electrolyzed water due to retention of the scale in communication
hole RTH is suppressed.
[0161] (7) Cathode 1C may contain a stainless steel material, and
high electrical resistance material R may contain a fluorine resin
material.
[0162] According to this, both the value of the adhesion strength
between cathode 1C and the coating material and a required
electrical resistance value are set to desired values.
[0163] (8) Electrolyzed water generation system 1000 includes
electrolyzed water generators 100A, 100B according to any one of
the above (1) to (7) and controllers CA, CB, CC, CD for controlling
electrolyzed water generators 100A, 100B. Controllers CA, CB, CC,
CD intermittently apply a voltage between anode 1A and cathode
1C.
[0164] According to this, while the application of the voltage
between anode 1A and cathode 1C is stopped, ozone retained between
anode 1A and cation exchange membrane 5 flows out into water
supplied to electrolyzed water generators 100A, 100B. Thus, it is
suppressed that ozone is retained between anode 1A and cation
exchange membrane 5. While the application of the voltage between
anode 1A and cathode 1C is stopped, hydrogen retained between
cation exchange membrane 5 and cathode 1C flows out into water
supplied to electrolyzed water generators 100A, 100B. Thus, it is
suppressed that hydrogen is retained between cation exchange
membrane 5 and cathode 1C.
[0165] (9) Electrolyzed water generation system 1000 may include
flow paths (15, 10A, 10B) through which water is supplied to
electrolyzed water generators 100A, 100B. Electrolyzed water
generation system 1000 may include pump P that supplies water to
flow paths (15, 10A, 10B) and flow path change mechanism V switched
so as to intermittently supply water from flow paths (15, 10A, 10B)
to electrolyzed water generators 100A, 100B. Controllers CA, CB,
CC, CD control pump P and flow path change mechanism V.
Consequently, water is supplied from flow paths (15, 10A, 10B) to
electrolyzed water generators 100A, 100B even during the period in
which no voltage is applied.
[0166] According to this, most of ozone retained between anode 1A
and cation exchange membrane 5 and most of hydrogen retained
between cation exchange membrane 5 and cathode 1C can be caused to
flow from electrolyzed water generators 100A, 100B to downstream
flow paths (20A, 20B).
[0167] (10) Electrolyzed water generation system 1000 includes
trunk flow path 15 to which raw water is supplied, first branch
flow paths 10A, 20A branched from trunk flow path 15, and second
branch flow paths 10B, 20B branched from trunk flow path 15 and
supplying the raw water, flowing through trunk flow path 15, to the
downstream of trunk flow path 15.
[0168] Electrolyzed water generation system 1000 includes
electrolyzed water generators 100A, 100B. Electrolyzed water
generators 100A, 100B include anode 1A, cathode 1C, and cation
exchange membrane 5 provided between anode 1A and cathode 1C.
Electrolyzed water generators 100A, 100B are connected to first
branch flow paths 10A, 20A and switched between the first
generation state where first electrolyzed water is generated from
raw water flowing through first branch flow paths 10A. 20A and the
first non-generation state where the first electrolyzed water is
not generated.
[0169] Flow path change mechanisms V, V1, V2 are switched between
the first state where raw water is supplied from trunk flow path 15
to first branch flow paths 10A, 20A and the second state where the
raw water is supplied from trunk flow path 15 to second branch flow
paths 10B, 20B.
[0170] According to the above configuration, when no voltage is
applied between anode 1A and cathode 1C, flow path change
mechanisms V V1, V2 can be switched to the second state such that
the raw water is not supplied to cation exchange membrane 5. This
can suppress that cation exchange membrane 5 incorporates cations
contained in the raw water. Thus, it is suppressed that when
electrolyzed water generators 100A, 100B are generating
electrolyzed water, that is, when a voltage is applied between
anode 1A and cathode 1C, the cations incorporated into cation
exchange membrane 5 are released into electrolyzed water. As a
result, scale generation due to the release of cations from cation
exchange membrane 5 to the electrolyzed water is suppressed. When
electrolyzed water generators 100A, 100B are not generating
electrolyzed water, water that is not electrolyzed water can be
taken out from second branch flow path 10B. Therefore, when
electrolyzed water generators 100A, 100B are not generating
electrolyzed water, it is possible to use water that is not
electrolyzed water while suppressing scale generation.
[0171] (11) Electrolyzed water generation system 1000 may further
include controllers CA, CB, CC, CD that control electrolyzed water
generators 100A, 100B. Controllers CA. CB, CC, CD intermittently
apply a voltage between anode 1A and cathode 1C and thereby
performs control to switch electrolyzed water generators 100A, 100B
from the non-generation state to the generation state.
[0172] According to the above configuration, the electrolyzed water
generator can generate electrolyzed water by switching to the
generation state where electrolyzed water is generated.
[0173] (12) In electrolyzed water generation system 1000, anode 1A
is first anode 1A. Cathode 1C is first cathode 1C. Cation exchange
membrane 5 is first cation exchange membrane 5. The generation
state is the first generation state. The non-generation state is
the first non-generation state. Electrolyzed water generators 100A
and 100B are first electrolyzed water generator 100A.
[0174] Electrolyzed water generation system 1000 includes second
electrolyzed water generator 100B. Electrolyzed water generator
100B includes second anode 1A, second cathode 1C, and second cation
exchange membrane 5 provided between second anode 1A and second
cathode 1C. Second electrolyzed water generator 100B is connected
to second branch flow paths 10B, 20B and switched between the
second generation state where second electrolyzed water is
generated from raw water flowing through second branch flow paths
10B, 20B and the second non-generation state where the second
electrolyzed water is not generated.
[0175] When electrolyzed water generator 100A described above is
continuously used, many ozone bubbles are retained between anode 1A
and cation exchange membrane 5, and many hydrogen bubbles are
retained between cathode 1C and cation exchange membrane 5. The
retained ozone bubbles and hydrogen bubbles form a local insulating
portion. Thus, the electrolysis ability of raw water decreases.
That is, the voltage applied between anode 1A and cathode 1C
increases. The scale adheres to cathode 1C due to an increase in
the pH of water. As a result, the ability to generate electrolyzed
water decreases. Thus, the time for continuously using each of
first electrolyzed water generator 100A and second electrolyzed
water generator 100B is shortened, or there is no alternative but
to give up the continuous use of each of first electrolyzed water
generator 100A and second electrolyzed water generator 100B.
However, according to the above configuration, the electrolyzed
water generator that generates electrolyzed water and the
electrolyzed water generator that does not generate electrolyzed
water are switched such that the period of use of each electrolyzed
water generator is divided, so that the period of use of each of
first electrolyzed water generator 100A and second electrolyzed
water generator 100B is shortened. On the other hand, electrolyzed
water is continuously generated. As a result, the ability to
generate electrolyzed water is improved.
[0176] (13) Electrolyzed water generation system 1000 may further
include first electrolyzed water generator 100A, second
electrolyzed water generator 100B, and controllers CA, CB, CC, CD
that control flow path change mechanism V. When controllers CA, CB,
CC, CD perform control to switch flow path change mechanism V from
the second state to the first state, controllers CA, CB, CC, CD
perform control to switch first electrolyzed water generator 100A
from the first non-generation state to the first generation state
during a period where second electrolyzed water generator 100B is
controlled to be switched from the second generation state to the
second non-generation state and flow path change mechanism V is
controlled to be switched from the second state to the first state.
When controllers CA, CB, CC, CD perform control to switch flow path
change mechanism V from the first state to the second state,
controllers CA, CB, CC, CD perform control to switch second
electrolyzed water generator 100B from the second non-generation
state to the second generation state during a period in which first
electrolyzed water generator 100A is controlled to be switched from
the first generation state to the first non-generation state and
flow path change mechanism V is controlled to be switched from the
first state to the second state.
[0177] According to the above configuration, controllers CA, CB
automatically suppress scale generation.
[0178] (14) Electrolyzed water generation system 1000 further
includes purification device 200 that is connected to second branch
flow paths 10B, 20B, generates purified water from raw water
flowing through second branch flow paths 10B, 20B, and supplies the
generated purified water to the downstream of second branch flow
paths 10B, 20B.
[0179] According to this, when electrolyzed water generators 100A,
100B do not generate electrolyzed water, purified water can be used
instead of raw water.
[0180] (15) Electrolyzed water generation system 1000 further
includes purification device 200 that is connected to trunk flow
path 15, generates purified water from raw water flowing through
trunk flow path 15, and supplies the generated purified water to
the downstream of trunk flow path 15.
[0181] In this case, electrolyzed water generators 100A, 100B
generate electrolyzed water from purified water. According to this,
since electrolyzed water is generated from purified water, the
possibility of foreign matters entering the insides of electrolyzed
water generators 100A, 100B is reduced. When electrolyzed water
generators 100A, 100B do not generate electrolyzed water, purified
water can be used instead of raw water.
[0182] (16) Flow path change mechanism V, V1, V2 have first
open/close valve V1 connected to first branch flow paths 10A, 20A
and second open/close valve V2 connected to second branch flow
paths 10B, 20B. In the first state, first open/close valve V1 is
opened, and second open/close valve V2 is closed. In the second
state, first open/close valve V1 is closed, and second open/close
valve V2 is opened.
[0183] According to the above configuration, when no voltage is
applied between anode 1A and cathode 1C, the states of first
open/close valve V1 and second open/close valve V2 can be switched
such that raw water is not supplied to cation exchange membrane 5.
This can suppress that cation exchange membrane 5 incorporates
cations contained in the raw water. Thus, it is suppressed that
when a voltage is applied between anode 1A and cathode 1C, the
cations incorporated into cation exchange membrane 5 are released
into electrolyzed water. As a result, scale generation due to the
release of cations from cation exchange membrane 5 to the
electrolyzed water is suppressed.
REFERENCE MARKS IN THE DRAWINGS
[0184] 1A: anode (first anode, second anode, electrode) [0185] 1C:
cathode (first cathode, second cathode, electrode) [0186] 1CTH:
cathode hole [0187] 1S: power supply body [0188] 1SA, 15C: shaft
attachment piece [0189] 5: cation exchange membrane [0190] 5TH:
membrane hole [0191] 10A: upstream-side first branch flow path
(flow path) [0192] 10B: upstream-side second branch flow path (flow
path) [0193] 15: trunk flow path (flow path) [0194] 20A:
downstream-side first branch flow path (flow path) [0195] 20B:
downstream-side second branch flow path (flow path) [0196] 100A:
first electrolyzed water generator (electrolyzed water generator)
[0197] 100B: second electrolyzed water generator [0198] 101:
housing [0199] 102: electrode case [0200] 103: electrode case lid
[0201] 104, 105: through-hole [0202] 106, 107: power supply shaft
[0203] 200: purification device [0204] 1000: electrolyzed water
generation system [0205] AC: AC power [0206] C1, C2: gap (groove or
cutout) [0207] C, CA, CB, CC, CD: controller [0208] I: input unit
[0209] M: memory [0210] P: pump [0211] PR: processor [0212] r:
resistor [0213] R: high electrical resistance material [0214] RTH:
communication hole [0215] S: sensor [0216] V: flow path change
mechanism [0217] V1, V2: open/close valve (flow path change
mechanism)
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